1. Field of Invention
The present invention relates to a selective one-way wrench.
2. Related Prior Art
In U.S. Pat. No. 4,420,995, there is disclosed a conventional selective one-way wrench including a head 1, a gear 10 and a direction controller (not shown) provided between the head 1 and the gear 10. The gear 10 includes an insert 9 for insertion in a socket 16 for engagement with a bolt or nut. A detent 12 is put in the insert 9. A pin 2 is put in the insert 9 for controlling the detent 12.
In Application US2003/0051583, there is disclosed a conventional one-way wrench including a head 11, a gear 40 and a one-way transmission provided between the head 11 and the gear 40. The one-way transmission includes a block 20, a pawl 50 and a spring 60 for connecting the pawl 50 to the block 20. This conventional one-way wrench can be used to drive a bolt or nut in a direction, but cannot be used to drive the bolt or nut in an opposite direction unless it is turned upside down. However, if the gear 40 is of the type that includes an insert for insertion in a socket for engagement with a bolt or nut, such turning will be impossible in use. Therefore, there is no adequate reason for modifying this conventional one-way wrench by including the gear 10 formed with the insert 9, the detent 12 and the gear 10 disclosed in U.S. Pat. No. 4,420,995.
The present invention is therefore intended to obviate or at least alleviate the problems encountered in prior art.